Excerpts from Murray, Paul (HP Cloud Services)'s message of 2014-01-27 04:14:44 -0800: > Hi Justin, > > My though process is to go back to basics. To perform discovery there is no > getting away from the fact that you have to start with a well-known address > that your peers can access on the network. The second part is a > service/protocol accessible at that address that can perform the discovery. > So the questions are: what well-known addresses can I reach? And is that a > suitable place to implement the service/protocol. > > The metadata service is different to the others in that it can be accessed > without credentials (correct me if I'm wrong), so it is the only possibility > out of the openstack services if you do not want to have credentials on the > peer instances. If that is not the case then the other services are options. > All services require security groups and/or networks to be configured > appropriately to access them. > > (Yes, the question "can all instances access the same metadata service" did > really mean are they all local. Sorry for being unclear. But I think your > answer is yes, they are, right?) > > Implementing the peer discovery in the instances themselves requires some > kind of multicast or knowing a list of addresses to try. In both cases either > the actual addresses or some name resolved through a naming service would do. > Whatever is starting your instances does have access to at least nova, so it > can find out if there are any running instances and what their addresses are. > These could be used as the addresses they try first. These are the way that > internet p2p services work and they work in the cloud. >
That's kind of my point about using Heat. You can use any higher level tool to achieve this by dropping the existing addresses into userdata and then using a gossip protocol to "spread the word" to existing nodes about new ones. _______________________________________________ OpenStack-dev mailing list [email protected] http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
